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What follows the diagnosis of molar pregnancy?
The uterus will be emptied of its contents, usually by suction curettage under a general anaesthetic.
Occasionally, severe bleeding complicates the procedure and blood transfusion may be necessary.
What kind of follow-up is required after treatment for molar pregnancy?
Molar pregnancy is a benign condition but with a malignant potential.
The potential remains for several months after the evacuation of the uterus. Follow-up is recommended for about one or two years, during which you should not try to conceive. Most experts consider one year to be adequate.
Follow-up normally involves the patient giving urine samples at timed intervals, which may be weekly at first, then fortnightly, monthly and so on. Pregnancy hormone levels in the urine are quantified. These are expected to fall steeply to virtually undetectable levels within weeks of the evacuation. Needless to say, pregnancy, during this follow-up period will complicate the picture.
What happens if the hormone levels do not fall as expected during the follow-up?
It may mean that the patient has what is known as a "persistent mole", an invasive mole or, more seriously, a malignant transformation into what is known as choriocarcinoma.
Tests will be carried out to verify which is which. Treatment in the form of chemotherapy will almost certainly be embarked on. Success with treatment is excellent, even with choriocarcinoma, provided it is started in time. This is the essence of close follow-up.
What proportion of molar pregnancies will transform into the malignant form (choriocarcinoma)?
Probably less than 5 per cent. The risk of transformation depends on several factors and is higher among those who have a previous history of molar pregnancy and older mothers (i.e. those above thirty-nine years of age). It is, however, important to stress that all affected mothers need the close follow-up.
Are there any known predisposing factors to molar pregnancy?
No. Curiously, this condition is most common in the Far East where, in some countries such as Taiwan, molar pregnancies constitute about 1 per cent of all pregnancies. Compare this with less than 0.05 per cent in western Europe (or 1 in 2000), which means it is more than twenty times commoner in some countries of the Far East compared to western Europe.
Does this mean it is likely to be environmental or genetic?
No. If it was environmental, you would expect Caucasians in the Far East to have increased incidence, to match the natives of those countries.. This has not happened. On the other hand, in countries such as the USA with a large immigrant community from the Far East, the incidence of molar pregnancy among them appears to be the same as that of other ethnic groups and is nowhere near that seen in their ancestral lands.
The important predisposing factors therefore remain elusive.
Does the use of chemotherapy after molar pregnancy mean that it has turned into cancer?
Not at all. About one in five patients with molar pregnancy will need chemotherapy. In fact, for the majority of these, it will be because of what is known as a persistent mole. This is a warning sign that malignant transformation may follow. Chemotherapy is therefore a pre-emptive strike.
Less than a quarter of those receiving chemotherapy do so because of a malignant transformation.